Regioselective Cage Opening of La sub(2)[at]D sub(2)(10611)-C sub(72) with 5,6-Diphenyl-3-(2-pyridyl)-1,2,4-triazine

• Published in: Angewandte Chemie Vol. 127; no. 7; pp. 2260 - 2263
• Main Authors: Yamada, Michio, Muto, Yasuhiro, Kurihara, Hiroki, Slanina, Zdenek, Suzuki, Mitsuaki, Maeda, Yutaka, Rubin, Yves, Olmstead, Marilyn M, Balch, Alan L, Nagase, Shigeru, Lu, Xing, Akasaka, Takeshi
• Format: Journal Article
• Language: English
• Published: 01.02.2015
• Subjects: Bonding; Cage; Derivatives; Electrode potentials; Elongation; Isomers; Metallofullerenes; X-rays
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201410012

The thermal reaction of the endohedral metallofullerene La sub(2)[at]D sub(2)(10611)-C sub(72), which contains two pentalene units at opposite ends of the cage, with 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine proceeded selectively to afford only two bisfulleroid isomers. The molecular structure of one isomer was determined using single-crystal X-ray crystallography. The results suggest that the [4+2] cycloaddition was initiated in a highly regioselective manner at the C--C bond connecting two pentagon rings of C sub(72). Subsequent intramolecular electrocyclization followed by cycloreversion resulted in the formation of an open-cage derivative having three seven-membered ring orifices on the cage and a significantly elongated cage geometry. The reduction potentials of the open-cage derivatives were similar to those of La sub(2)[at]D sub(2)-C sub(72) whereas the oxidation potentials were shifted more negative than those of La sub(2)[at]D sub(2)-C sub(72). These results point out that further oxidation could occur easily in the derivatives.Original Abstract: Fullerene im OP: Die thermische Reaktion des endohedralen Metallofullerens La sub(2)[at]D sub(2)(10611)-C sub(72) mit 5,6-Diphenyl-3-(2-pyridyl)-1,2,4-triazin liefert selektiv nur zwei Bisfulleroid-Isomere. Die Rontgen-kristallographische Analyse eines Isomers (siehe Bild) belegt die Bildung eines geoffneten Derivats mit drei siebengliedrigen Ringen und laenglichem Kaefig.